/*
 * FXGL - JavaFX Game Library. The MIT License (MIT).
 * Copyright (c) AlmasB (almaslvl@gmail.com).
 * See LICENSE for details.
 */
package com.almasb.fxgl.physics.box2d.common;

import com.almasb.fxgl.core.math.Vec2;

import java.io.Serializable;

/**
 * A 3-by-3 matrix. Stored in column-major order.
 *
 * @author Daniel Murphy
 */
public class Mat33 implements Serializable {
    private static final long serialVersionUID = 2L;

    public static final Mat33 IDENTITY = new Mat33(new Vec3(1, 0, 0), new Vec3(0, 1, 0), new Vec3(0, 0, 1));

    public final Vec3 ex, ey, ez;

    public Mat33() {
        ex = new Vec3();
        ey = new Vec3();
        ez = new Vec3();
    }

    public Mat33(float exx, float exy, float exz, float eyx, float eyy, float eyz, float ezx,
                 float ezy, float ezz) {
        ex = new Vec3(exx, exy, exz);
        ey = new Vec3(eyx, eyy, eyz);
        ez = new Vec3(ezx, ezy, ezz);
    }

    public Mat33(Vec3 argCol1, Vec3 argCol2, Vec3 argCol3) {
        ex = argCol1.clone();
        ey = argCol2.clone();
        ez = argCol3.clone();
    }

    public void setZero() {
        ex.setZero();
        ey.setZero();
        ez.setZero();
    }

    public void set(float exx, float exy, float exz, float eyx, float eyy, float eyz, float ezx,
                    float ezy, float ezz) {
        ex.x = exx;
        ex.y = exy;
        ex.z = exz;
        ey.x = eyx;
        ey.y = eyy;
        ey.z = eyz;
        ez.x = eyx;
        ez.y = eyy;
        ez.z = eyz;
    }

    public void set(Mat33 mat) {
        Vec3 vec = mat.ex;
        ex.x = vec.x;
        ex.y = vec.y;
        ex.z = vec.z;
        Vec3 vec1 = mat.ey;
        ey.x = vec1.x;
        ey.y = vec1.y;
        ey.z = vec1.z;
        Vec3 vec2 = mat.ez;
        ez.x = vec2.x;
        ez.y = vec2.y;
        ez.z = vec2.z;
    }

    public void setIdentity() {
        ex.x = (float) 1;
        ex.y = (float) 0;
        ex.z = (float) 0;
        ey.x = (float) 0;
        ey.y = (float) 1;
        ey.z = (float) 0;
        ez.x = (float) 0;
        ez.y = (float) 0;
        ez.z = (float) 1;
    }

    // Multiply a matrix times a vector.
    public static final Vec3 mul(Mat33 A, Vec3 v) {
        return new Vec3(v.x * A.ex.x + v.y * A.ey.x + v.z + A.ez.x, v.x * A.ex.y + v.y * A.ey.y + v.z
                * A.ez.y, v.x * A.ex.z + v.y * A.ey.z + v.z * A.ez.z);
    }

    public static final Vec2 mul22(Mat33 A, Vec2 v) {
        return new Vec2(A.ex.x * v.x + A.ey.x * v.y, A.ex.y * v.x + A.ey.y * v.y);
    }

    public static final void mul22ToOut(Mat33 A, Vec2 v, Vec2 out) {
        final float tempx = A.ex.x * v.x + A.ey.x * v.y;
        out.y = A.ex.y * v.x + A.ey.y * v.y;
        out.x = tempx;
    }

    public static final void mul22ToOutUnsafe(Mat33 A, Vec2 v, Vec2 out) {
        assert v != out;
        out.y = A.ex.y * v.x + A.ey.y * v.y;
        out.x = A.ex.x * v.x + A.ey.x * v.y;
    }

    public static final void mulToOut(Mat33 A, Vec3 v, Vec3 out) {
        final float tempy = v.x * A.ex.y + v.y * A.ey.y + v.z * A.ez.y;
        final float tempz = v.x * A.ex.z + v.y * A.ey.z + v.z * A.ez.z;
        out.x = v.x * A.ex.x + v.y * A.ey.x + v.z * A.ez.x;
        out.y = tempy;
        out.z = tempz;
    }

    public static final void mulToOutUnsafe(Mat33 A, Vec3 v, Vec3 out) {
        assert out != v;
        out.x = v.x * A.ex.x + v.y * A.ey.x + v.z * A.ez.x;
        out.y = v.x * A.ex.y + v.y * A.ey.y + v.z * A.ez.y;
        out.z = v.x * A.ex.z + v.y * A.ey.z + v.z * A.ez.z;
    }

    /**
     * Solve A * x = b, where b is a column vector. This is more efficient than computing the inverse
     * in one-shot cases.
     *
     * @param b
     * @return
     */
    public final Vec2 solve22(Vec2 b) {
        Vec2 x = new Vec2();
        solve22ToOut(b, x);
        return x;
    }

    /**
     * Solve A * x = b, where b is a column vector. This is more efficient than computing the inverse
     * in one-shot cases.
     *
     * @param b
     * @return
     */
    public final void solve22ToOut(Vec2 b, Vec2 out) {
        final float a11 = ex.x, a12 = ey.x, a21 = ex.y, a22 = ey.y;
        float det = a11 * a22 - a12 * a21;
        if (det != 0.0f) {
            det = 1.0f / det;
        }
        out.x = det * (a22 * b.x - a12 * b.y);
        out.y = det * (a11 * b.y - a21 * b.x);
    }

    // djm pooling from below

    /**
     * Solve A * x = b, where b is a column vector. This is more efficient than computing the inverse
     * in one-shot cases.
     *
     * @param b
     * @return
     */
    public final Vec3 solve33(Vec3 b) {
        Vec3 x = new Vec3();
        solve33ToOut(b, x);
        return x;
    }

    /**
     * Solve A * x = b, where b is a column vector. This is more efficient than computing the inverse
     * in one-shot cases.
     *
     * @param b
     * @param out the result
     */
    public final void solve33ToOut(Vec3 b, Vec3 out) {
        assert b != out;
        Vec3.crossToOutUnsafe(ey, ez, out);
        float det = Vec3.dot(ex, out);
        if (det != 0.0f) {
            det = 1.0f / det;
        }
        Vec3.crossToOutUnsafe(ey, ez, out);
        final float x = det * Vec3.dot(b, out);
        Vec3.crossToOutUnsafe(b, ez, out);
        final float y = det * Vec3.dot(ex, out);
        Vec3.crossToOutUnsafe(ey, b, out);
        float z = det * Vec3.dot(ex, out);
        out.x = x;
        out.y = y;
        out.z = z;
    }

    public void getInverse22(Mat33 M) {
        float a = ex.x, b = ey.x, c = ex.y, d = ey.y;
        float det = a * d - b * c;
        if (det != 0.0f) {
            det = 1.0f / det;
        }

        M.ex.x = det * d;
        M.ey.x = -det * b;
        M.ex.z = 0.0f;
        M.ex.y = -det * c;
        M.ey.y = det * a;
        M.ey.z = 0.0f;
        M.ez.x = 0.0f;
        M.ez.y = 0.0f;
        M.ez.z = 0.0f;
    }

    // / Returns the zero matrix if singular.
    public void getSymInverse33(Mat33 M) {
        float bx = ey.y * ez.z - ey.z * ez.y;
        float by = ey.z * ez.x - ey.x * ez.z;
        float bz = ey.x * ez.y - ey.y * ez.x;
        float det = ex.x * bx + ex.y * by + ex.z * bz;
        if (det != 0.0f) {
            det = 1.0f / det;
        }

        float a11 = ex.x, a12 = ey.x, a13 = ez.x;
        float a22 = ey.y, a23 = ez.y;
        float a33 = ez.z;

        M.ex.x = det * (a22 * a33 - a23 * a23);
        M.ex.y = det * (a13 * a23 - a12 * a33);
        M.ex.z = det * (a12 * a23 - a13 * a22);

        M.ey.x = M.ex.y;
        M.ey.y = det * (a11 * a33 - a13 * a13);
        M.ey.z = det * (a13 * a12 - a11 * a23);

        M.ez.x = M.ex.z;
        M.ez.y = M.ey.z;
        M.ez.z = det * (a11 * a22 - a12 * a12);
    }

    public final static void setScaleTransform(float scale, Mat33 out) {
        out.ex.x = scale;
        out.ey.y = scale;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((ex == null) ? 0 : ex.hashCode());
        result = prime * result + ((ey == null) ? 0 : ey.hashCode());
        result = prime * result + ((ez == null) ? 0 : ez.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) return true;
        if (obj == null) return false;
        if (getClass() != obj.getClass()) return false;
        Mat33 other = (Mat33) obj;
        if (ex == null) {
            if (other.ex != null) return false;
        } else if (!ex.equals(other.ex)) return false;
        if (ey == null) {
            if (other.ey != null) return false;
        } else if (!ey.equals(other.ey)) return false;
        if (ez == null) {
            if (other.ez != null) return false;
        } else if (!ez.equals(other.ez)) return false;
        return true;
    }
}
